Magnetic switch



March 4, 1941. uss 2,233,757

MAGNETIC SWITCH Filed Jan. 27, 1938 4 Sheets-Sheet 1 INVENTOR. G. L USSELMAN ATTORNEY.

March 4, 1941. e. L. USSELMAN MAGNET IC SWITCH Filed Jan. 27, 1958 4 Sheets-Sheet 2 INVENTOR. G U55 EL MA N ATTORNEY.

March 4, 1941.

G/L. USSELMAN MAGNET I C SWITCH Filed Jan. 2'7, 193B 4 Sheets-Sheet I5 INVENTOR G.L. USSELMAN 7% m ATTORNEY.

March 4,1941;

G. L. USSELMAN 2,233.75?

MAGNETIC SWITCH Filed Jan. 27, 1938 4 Sheets-Sheet 4 INVENTOR. 5. L. 1555mm ATTORNEY.

Patented Mar. 4, 1941 UNITED STATES PATENT OFFICE MAGNETIC SWITCH Application January 27, 1938, Serial No. 187,124

7 Claims.

This invention relates to magnetic switches or contactors and especially to improvements on magnetic switches for saving or economizing in the use of electrical power used to operate the switch.

The practice in prior art has been to use one electro-magnet to close the switch and hold it closed. A comparatively powerful magnet is required to close the switch and hold it closed because of the large air gap present in the magnetic circuit. This air gap is necessarily and inherently large when the contactor or switch is open and the air gap is still comparatively large when the switch is closed. A comparatively large amount of iron is generally used for the magnetic circuit. For these reasons, a comparatively large amount of electrical power is required to operate the magnetic switch.

An object of this invention is to reduce the operating power required to hold the contactor closed.

Another object of this invention is to provide an auxiliary holding magnet which holds the contactor closed and further provides means for 25 de-energizing the main armature magnet coil.

The present invention will best be understood by referring to the accompanying drawings, in which:

Fig. l is a front elevation of an improved contactor of this invention and an interlock switch which operates in conjunction with the magnets of the contactor; shown also in Fig. 4;

Fig. 1a. is a side view of Fig. 1;

Fig. 1b is a partial plan view showing the 35 auxiliary magnet;

Fig. 2 is a front elevation of another modification of this invention;

Fig. 2a is a side view of Fig. 2;

Fig. 3 is a front elevation of a further modification of this invention;

Fig. 3a is a side View of Fig. 3;

Fig. 4 is a side view of the interlock switch; and

Fig. 5 is a circuit diagram showing the switch contacts and coils of this invention.

Referring now in detail to the drawings:

The letter A indicates the main magnet core, B the main magnet armature, and C the coil of the main magnet contactor. all of which are mounted on a. frame Fr. The armature B is mounted upon a movable member A1" which is pivotally arranged upon a shaft S. Armature B is provided with a stop ST which prevents the contactor from opening too far. Located upon the shaft S and insulated from it are a plurality of circuit contactors 20, 2i, 22 and 23, the numbers of which are not necessarily limited to four, but are only indicated as such to describe this invention.

To the lower portion of frame member Fr there is provided metallic supporting members 8. 9 and I0, which are bolted to the main contactor frame by means of a plurality of bolts 24. Two link toggle members I and 2 are supported by a bearing 3 located on the lower frame member 9, the upper portion of link 2 being pivoted to the armature Ar of the contactor by means of a pivot 25. A core D and coil F are supported as shown by means of two support members 'I which are bolted to the side frame member 8. An armature E is attached to toggle member I and by means of a pivot 26 is bolted to a bearing 6, the upper end of toggle member I being joined to toggle member 2 by means of a bearing 5 and pivot 21.

To the right of Fig. 1, there is shown an interlock switch which operates in conjunction with the main magnet armature. This interlock is mounted upon a panel near the end of the shaft S and for the sake of clarity is not shown in the side View Fig. 10 but is described and illustrated in more detail by the side view Fig. 4. Arm II is attached to line up with the interlock switch on shaft S by an insulating bushing I3 and clamped by means of a U-bolt I2 and nuts 28. Arm II carries the adjustable pin I00 as shown, secured by nut IOI. Interlock switch arm I4 is pivoted by pivot 29 on hearing I5, which is secured to the panel by means of a screw or stud I5a. Flexible lead I8 forms the electrical connection between the two. A leaf spring I6 is riveted to arm I4 by means of rivets Ilia. The coil spring I1 is held in place by means of a stud I9 and nuts I9a. This stud also serves as a stop to prevent arm I4 from moving too far. The end portion I4 of arm I4 carries a contact 30. Stud 33 is bolted to the panel and carries a contact 3|. The outgoing leads 4| and 42 are connected to studs IEa and 33a, as shown. Member 44 indicates the base of a bearing for one end of the shaft S.

In Fig. 1b. a plan view of the auxiliary holding magnet is shown. It will be noted that there are two toggle members I and 2 on each side. These two side members operate in parallel, the complete contact assembly being mounted upon the panel, as shown in Figs. 1 and 1a. Electrical connections are made from the coil C by means of leads L and from the coil F by leads L.

Figs. 2 and 2a. show another modification of this invention wherein the auxiliary magnet coil F is mounted upon core D and supported by members H, while the armature E is connected upon the main contactor armature by means of members Q. This relay magnet has no air gap when the contactor is closed and its leverage is somewhat greater than that of the main magnet armature B.

Figs. 3 and 3a are still further modifications and somewhat different from Figs. 2 and 2a in that the auxiliary magnet core D is formed as part of the main magnet core A and the auxiliary magnet core E is also a part of the main magnet armature B, which in each case requires the addition of more magnetic material, such as iron to the main magnet core and armature. A slot 50 is out across the face of the upper part of the main magnet core and coil F is placed upon the auxiliary coil core, as shown. The stop pin. ST is located on the lower portion of the contact arm Ar, as shown, in order to prevent interference with the operation of coil F.

In the normal operation of an ordinary contactor or magnetic switch of the prior art type, the contactor is operated by some electrical control system which energizes the main magnet such as coil C. This pulls up and later closes the armature B, which is bolted to the arm AT, the latter being clamped to shaft S, and causes the shaft to rotate through several degrees. Shaft S usually carries one or more contact fingers, such as is indicated by numerals 20 to 23, inclusive, which are insulated from the shaft but are generally part of some other external cincuit or circuits.

The operation of the improved contactor of this invention, as shown by Fig. 5, is different from that of the ordinary contactor in that when the contacts of the contactor are open, the interlock switch contacts 30 and 3| are closed by extension of spring l1. When the control current is applied from an external electrical control circult, both magnetic coils C and F on the main and auxiliary magnets are energized and all contacts except 30 and 3| are closed. While the armatures B and E are open, practically all the pulling force for closing the contacts is applied by the main magnet. When the main armature B closes within about to A" from the faces of the magnet core A, the pin I00 touches the spring Hi of interlock switch arm I4; however, due to the inertia of arm l4, it does not move immediately, thus producing a slight time delay. The space between spring I6 and arm M, as shown in Fig. 4, is made such that when the main contactor is closed, the contacts 30 and 3| can remain closed, in which case the spring I6 can be depressed but would not touch the arm 14. Due to the high velocity of main armature B, it will close before the arm I of the interlock switch can open contacts 30 and 3| and as mentioned above, spring 16 will be depressed a greater distance. Now, since the main armature is closed, the toggle members I and 2 will cause the auxiliary armature E to also close; due primarily to the increased leverage of the toggle, and because the auxiliary magnet D and armature E has no large air gap, the pull of the small auxiliary magnet is sufficient to hold the main armature B.

of the contactor closed. After the contactor has closed, the depressed spring I6 overcomes the inertia of interlock arm I4 and the pressure of coil spring l1, and arm H is pressed down against the stop pin 19. This opens contacts 30 and 3|, which breaks the circuit of the main magnet coil C so that it is no longer energized but auxiliary coil F is energized and holds all contacts except 30 and 3| closed. While the auxiliary coil F holds the contactor closed, it should be noted that the toggles I and 2 are not straight, otherwise the contacts would not open again. They should be set with an outward bend of several degrees to allow the contacts to open properly. Too much bend will require more holding force than is economical in the auxiliary holding magnet. When the external control voltage is re moved, the auxiliary holding magnet releases the toggle and the contacts all open, which closes the interlock switch contacts 30 and. 3| so that the main magnet is again ready for the closing operation when an external control voltage is again applied. Of several contactors which were tested, it was found that the main contactor magnet normally used about sixty-five watts of power. By means of this invention, the power required was reduced to above five watts. In particularly large contactors, where several hundred watts are required, this invention would permit a considerable saving.

The arrangements of this invention shown in Figs. 2 and 3 are simpler and have less moving parts than that shown in Fig. 1. Although the general principle of operation is the same in Figs. 1, 2 and 3, the arrangements shown in Fig. 2 and Fig. 3 will withstand operating wear much longer than the arrangement shown in Fig. 1 and Fig. la.

The invention should not be limited to the modification shown as it is capable of taking other forms and shapes.

What is claimed is:

l. A magnetic contactor comprising a core member, a main armature pivoted with respect to said core member, an auxiliary armature located adjacent and linked to said main armature, a first magnetic coil mounted on said core member for moving said main armature, a second magnetic coil for moving said auxiliary armature, a movable shaft secured to said main armature, a plurality of switch contacts secured to said movable shaft, a switch member arranged near said movable shaft and coupled thereto so that its contacts open to release the energizing voltage on said first magnet after said main armature is closed whereby voltage applied to said second magnetic coil holds said plurality of switch contacts closed.

2. A magnetic contactor comprising a core member, a main armature pivoted with respect to said core member, a toggle member linked to said main armature, an auxiliary armature located adjacent and linked to said main armature by said toggle member, a first magnetic coil mounted on said core member for moving said main armature, a second magnetic coil for moving said auxiliary armature, a movable shaft secured to said main armature, a plurality of switch contacts secured to said movable shaft, a switch member arranged near said movable shaft and coupled thereto so that its contacts open to release the energizing voltage on said first magnetic coil after said main armature is closed and said toggle member holding said plurality of switch con tacts closed by the voltage applied to said second coil.

3. A magnetic contactor member, a main armature pivoted with respect to said core member, a toggle member linked to said main armature, an auxiliary armature located adjacent and linked to said main armature by said toggle member, a first magnetic coil s comprising a core mounted on said core member for moving said main armature, a second magnetic coil for moving said auxiliary armature, a movable shaft connected to said main armature, a plurality of switch contacts secured to said movable shaft, a switch member having time delay means arranged near said movable shaft and coupled thereto so that its contacts open to release the energizing voltage on said first magnetic coil after said main armature is closed and said toggle member holding said plurality of switch contacts closed by the voltage applied to said second coil.

4. A magnetic contactor comprising a core member, a main armature pivoted on said core member, an auxiliary armature located adjacent and linked to said main armature, a first magnetic coil for moving said main armature, a second magnetic coil for moving said auxiliary armature, said first and second magnetic coils both mounted upon said core member, a movable shaft secured to said main armature, a plurality of switch contacts secured to said movable shaft, a switch member arranged near said movable shaft and coupled thereto so that its contacts open to release the energizing voltage on said first magnet after said main armature is closed whereby the voltage applied to said second magnetic coil holds said plurality of switch contacts closed.

5. A magnetic contactor comprising a core member, a main armature pivoted to said core member, a pair of toggle members linked to said main armature, an auxiliary armature located adjacent and linked to said main armature by said toggle members, a first magnetic coil mounted on said core member for moving said main armature, a second core member, a second magnetic coil for moving said auxiliary armature and mounted on said second core member, a movable shaft secured to said main armature, a plurality of switch contacts secured to said movable shaft, a switch member arranged near said movable shaft and coupled thereto so that its contacts open to release the energizing voltage on said first magnetic coil after said main armature is closed and said toggle member holding said plurality of switch contacts closed by the voltage applied to said second coil.

6. A magnetic contactor comprising a core member, a main armature pivoted to said core member, a toggle member linked to said main armature, an auxiliary armature located adjacent and linked to said main, armature by said toggle member, a first magnetic coil for moving said main armature, a second magnetic coil for moving said auxiliary armature, a movable shaft secured to said main armature, a plurality of switch contacts secured to said movable shaft, an arm insulatingly supported on said shaft, a switch member arranged near said arm insulatingly supported by said shaft so that its contacts open to release the energizing voltage on said first magnet after said main armature is closed and said toggle member holding said plurality of switch contacts closed by the voltage applied to said second coil.

7. A magnetic contactor comprising a core member, a main armature pivoted to said core member, a toggle member linked to said main armature, an auxiliary armature located adjacent and linked to said main armature by said toggle member, a first magnetic coil for moving said 9 main armature, a second magnetic coil for moving said auxiliary armature, a movable shaft secured to said main armature, a plurality of switch contacts secured to said movable shaft, a switch member located near said shaft and having a spring element to provide a time delay so that its contacts open to release the energizing voltage on said first magnet after said main armature is closed and said toggle member holding said plurality of switch contacts closed by the voltage applied to said second coil.

GEORGE LINDLEY USSELMAN. 

